1. Field of the Invention
The present invention relates to a lens-fitted photo film unit with a data recording device that photographically records data, such as the date of photography, on a filmstrip contained in the lens-fitted photo film unit.
2. Background Arts
Many types of lens-fitted photo film units have been known and sold in the market, that contain a roll of unexposed photo filmstrip and have simple photographic mechanisms for taking pictures on the filmstrip. Hereinafter, the lens-fitted photo film unit will be referred to as a film unit.
Recently, a film unit with a data recording device have been suggested, wherein data displayed on a data display device, such as the date of photography displayed on an LCD (liquid crystal display) panel, is photographically recorded on the filmstrip. On the other hand, cameras with such a data recording device have already been known in the art. Most of the data recording devices incorporated in the cameras use a specific light source, e.g. an LED. However, since the specific light source and a specific circuit for driving the light source increase the production cost and complicate the internal construction, it is not preferable to mount this kind of data recording device in the film unit because the film unit is expected to be simple in construction, and produced at a low cost.
To solve this problem, a data recording device for a film unit has been suggested in a prior art, which is provided with a light converging device, such as a condenser lens, so as to use external light for photographing data on the filmstrip. To enable photographing data on the filmstrip even when the exterior or the room is dark, this prior art suggests using a flash light that is projected from a flash device of the film unit and reflected from a photographic subjected, and then enters through the light converging device into the film unit.
This solution does not need a specific light source for the data recording device, and thus the data recording device does not electrically and mechanically complicate the film unit. However the intensity of the external light obtained through the light converging device, including the flash light reflected from the subject, is not always sufficient for recording data at an adequate density on the filmstrip.